Baylink Lab News

June 15th, 2024 Our research on bacterial vampirism has generated a lot of interest in the infectious disease community!

The research was highlighted in a WSU press release (here) and has received nearly 900 million views across multiple news outlets. The research was featured on news broadcasts in the Portland area, Chicago, and on Global News Canada.

Dr. Baylink also gave an interview with Contagion Live (here), describing how these new findings may help improve understanding of how individuals with inflammatory bowel diseases are susceptible to bloodstream infections by Enterobacteriaceae bacteria.

Pictured is Siena Glenn, co-lead author on the study.

June 6th, 2024 The final version of our new article ‘bacterial vampirism’ has been published in eLife here.

In this study we describe a novel pathogenesis behavior in which Enterobacteriaceae bacteria exhibit chemoattraction to human serum and are able to use nutrients in serum for growth. We propose bacterial vampirism could be involved with bacterial bloodstream infections by Enterobacteriaceae species.

We were also honored to have our article selected for a ‘Digest’ by the eLife team, which you can read here.

 

March 2024 Eliza Johnson joins the group as an undergraduate research assistant! Eliza is assisting with structural and molecular studies related to chemotaxis proteins. Learn more about her interests and background on our lab members page here.

 

 

Jan. 21st 2024 We report a new study on how bacteria of the gut use chemotaxis to navigate landscapes that contain mixtures of chemoattractant and chemorepellent stimuli.

Navigating contradictions: Salmonella Typhimurium chemotactic responses to conflicting chemoeffector signals show parity with bacterial growth benefits

Available now on Biorxiv: https://doi.org/10.1101/2023.07.07.548164

Abstract:

Many bacteria that colonize the guts of animals use chemotaxis to direct swimming motility and select sites for colonization based on sources of effectors derived from the host, diet, and microbial competitors of the local environ. The complex ecosystem of the gastrointestinal tract contains mixtures of chemoattractants and chemorepellents, but it remains poorly understood how swimming bacteria navigate conflicting signals. The enteric pathogen Salmonella Typhimurium possesses Tsr, a chemoreceptor protein that directs both chemoattraction and chemorepulsion responses, which we employed as a model to study chemotaxis in the presence of conflicting effector stimuli. We investigated how S. Typhimurium responds to human fecal matter, an effector source in the enteric lumen that contains high concentrations of indole, a bacteriostatic chemorepellent produced by the native commensals of the microbiota, and also nutrients such as L-serine, a chemoattractant. The indole concentration in human feces is more than 12-fold the concentration required for half-maximal chemorepulsion, however, we find S. Typhimurium, and various clinical isolates of non-typhoidal S. enterica serovars, are strongly attracted to liquid fecal matter. We further investigated the chemotactic responses of S. Typhimurium to titrations of indole and L-serine and revealed that chemorepulsion to indole is overridden in the presence of excess L-serine. We capture the inversion of these two opposing taxis behaviors in a phenomenon we define as “chemohalation” in which the bacteria organize into a halo around the treatment source with an interior zone of avoidance, which represents a compromise between chemoattraction and chemorepulsion. Growth analyses reveal that the chemotactic responses to these opposing effectors align chemoattraction and chemorepulsion with the relative growth of the bacteria in culture. Hence, our study supports the view that evolution has finely tuned chemotaxis to assess environmental habitability by evaluating the tradeoffs in bacterial growth based on the local combination of effectors.

Fall 2023 We had a lot going on this fall!

Andrea Gomez was awarded the Stone Scholarship.

Siena Glenn was awarded the Fowler Scholarship.

Kailie Franco was awarded the Kraft Scholarship.

Thanks to the creativity of Jyoti Kashyap, our lab won the Halloween door decorating contest! We also joined for a WSU volleyball match, but unfortunately they lost 🙁

Andrea, Siena, and Kailie presented their research at the CVM Research Symposium, and Andrea’s poster was selected as the featured departmental poster!


August 1st 2023 First year review!

Today marks one full year of the Baylink Lab being in operation. In that time we assembled a functional laboratory, grew from a group of 1 to 7, published our first paper, completed our first research investigation, obtained our first grants, and completed our first in vivo study. We developed a cutting-edge microscopy approach for studying bacterial chemosensing, grew protein crystals and collected diffraction data, and hosted Receptorfest 2023. We overcame -80 thaw emergencies, CO2 incubator malfunctions, broken elevators, and power losses to the building.

It was an amazing year of accomplishments, persistence, and a great foundation to continue to grow our laboratory.

July 7th 2023 First study from the Baylink lab!

Our research implicates bacterial chemotaxis as a mechanism involved in bacteremia and sepsis through driving pathogens to be attracted to sites of bleeding.

Available now on Biorxiv: https://doi.org/10.1101/2023.07.07.548164

Abstract:

Severe bacterial infections of the gastrointestinal (GI) tract instigate GI hemorrhaging that can lead to bacteremia, sepsis, and death. Pathogens preferentially colonize sites of injury, delaying healing and exacerbating tissue damage, but the underlying mechanisms are not well understood. We find that Enterobacteriaceae species are remarkably sensitive to human serum and perceive femtoliter quantities as a potent attractant. This behavior is driven by chemotaxis and the Tsr chemoreceptor, which recognizes L-serine present in serum. By studying the crystal structure of Salmonella Typhimurium Tsr, we identified a recognition motif for L-serine and found similar Tsr homologues in various Enterobacteriaceae species, including World Health Organization priority pathogens. Our analyses of Escherichia and Citrobacter bacteria, which also possess Tsr, confirm that these species exhibit chemoattraction to serum. We have coined the term ‘vampirism’ to describe this pathogenesis strategy and suggest it plays a role in injury tropism and increases the risk of bacteremia.

June 14th 2023 Intramural grant funded through College of Veterinary Medicine!

We are thankful for an award of $20,000 through WSU and CVM to support our infection model studies of Enterobacteriaceae pathogens.

The outstanding local veterinary and pathology expertise is a huge asset to our research and will serve to strengthen our in vivo studies.

June 13th 2023

A beautiful rendition of our laboratory, courtesy of artist Cameron Coyle.

May 12th 2023 Samira Diaz De Leon selected as a MARC program scholar!

The MARC-WSU program is funded by the National Institutes of Health and provides two years of support for undergraduate students in their junior and senior years

Samira was selected for this prestigious program and will begin in the fall of 2023. Congratulations!

Find out more about the MARC program here.

May 1st 2023 Our chemotaxis review is published!

Our review titled “Bacterial chemotaxis in human diseases” was published in Trends in Microbiology and featured on the cover of the May issue. This review examines the evidence that bacterial chemotaxis plays roles in human infections and how these systems might be targeted with new antibacterial strategies.

Read the article here.

March. 23rd 2023 New group photo!

The Baylink lab got together for the first College of Veterinary Medicine ‘Research Mixer’ and took the opportunity to snap a a new group photo.

March. 10th 2023 Exponential growth!

The Baylink lab welcomes two new members: Postdoctoral Researcher Dr. Jyoti Kashyap, and Doctoral Student Andrea Gomez.

Read more about their interests here.

Nov. 22nd 2022

A brief article featuring some highlights of our research interests: https://vetmed.wsu.edu/meet-our-researchers-dr-arden-baylink/

Nov. 8th 2022 -ASM NORTHWEST BRANCH MEETING 2022, GONZAGA UNIVERSITY, SPOKANE, WA

The Baylink lab attended ASM NW, making this meeting the first conference for our new research group. It was terrific to meet our Pacific Northwest microbiologists and learn about all the fascinating and diverse research going on in the region.

Nov. 5th, 2022

Our review article entitled “Bacterial Chemotaxis in Human diseases” was accepted for publication in Trends in Microbiology. Our work was also selected for the cover of the May 2023 issue. Congratulations to first-author Bibi Zhou!

August 1st, 2022

Kailie Franco and Siena Glenn join the Baylink lab as doctoral students. Read more about their interests here.

July 30th, 2022

The Baylink lab is officially in operation!